Light controlling device



April 1934' E. F. MEKELBURG 1,955,555

LIGHT CONTROLLING DEVICE Filed Sept. 15. 1952 INVENTOR.

ATTORNEYeS.

Patented Apr. 17, 1934' UNITED STATES PATENT OFFICE 1.955555 uon'r oonrnonmvc navroa Earl F. Mekelburg, Wauwatosa, Wis.

Application September is, 1932, Serial No. 633,242 1': Claims. (of. 111-97) This invention relates in general to improvements in light controlling devices and more particularly to devices for controlling lights on vehicles. 5 It is one of the objects of this invention to provide a light controlling device utilizing a light-sensitive electric cell in a circuit arranged to cause automatic dimming of the lights of the vehicle upon which the device is used when the cell is acted upon by light from an external source such as the lights of an approaching car.

It is recognized that devices have been previously proposed for vehicle light control, utilizing properties of a light-sensitive selenium cell to vary the resistance of the light circuit, either directly or indirectly, through the medium of any electromagnetic relay. 1n the present invention,

however, the arrangement is entirely different,

involving as it does, multiple circuit light opera- 20 tion, and including safety features of vital importance. Also, in certain arrangements of it, an entirely different form of light-sensitive cell is employed.

A more specific object of the invention is to provide a light controlling device having means which permits selective control, that is, which permits use of the automatic feature or the cut-, ting out of the automatic feature, leaving purely manual control. v

A more specific object of the invention is to provide, in a light controlling device used in combination with a vehicle having double or multiple circuit lights, means for automatically transferring connections from the bright light circuit to the dim'light circuit and back again, in response to a light-sensitive cell and including also means for automatically preventing transfer of connections to the dim light circuit if effective illumination would not result due to L circuit defects, and further to cause retransfer automatically to the bright light circuit if defect occurs in the dim light circuit when the connections for the same are established in response to the light-sensitive cell.

A further object of the invention is to provide a light controlling device having means in combination with thetail or parking light to permit the automatic operation of said light in response to action of approaching light rays upon the light-sensitive cell.

A further object of the invention is to provide a device of the class described which. may be utilized either in connection with head lights of the double filament type, or in" connection with head lamps incorporating two separate lights for substantially the same purpose.

A further object of the invention is to provide a light-controlling device of the class described, having means for automatically transferring connections from one circuit to another in response to a light-sensitive cell, and including also means for automatically discriminating between operable and inoperable circuits to permit or prevent automatic transfer in response to the light-sensitive cell in accordance with circuit conditions, and further to automatically transfer connections from one circuit to another'irrespective of the functioning of the light-sensitive cell, if the circuit for which connections have been established should become inoperative due to filament or wiring failure to the end that the automatic device will always assure illumination so long as an operable circuit exists.

Afurther object of the invention is to provide a light controlling device which is relatively simple in construction, effective, and well adapted for the purpose described.

With the above and other objects in view, the invention consists of the improved light controlling device, and all its parts and combinations, as set forth in the claims, and all equivalents thereof.

In the accompanying drawing in which the same reference numerals designate the same parts in-all of the views:

Fig; 1 is a diagrammatic view of the wiringcircuit as used in connection with head lights of the double filament type;

Fig.2 is a fragmentary diagrammatic view showing portions of a similar circuit in connection with double bulb head lights; and

Fig. 3 is a diagrammatic view showing a modified form of the invention.

Referring first to Figure 1 of the drawing, it will be seen that the usual vehicle storage battery 6 has one terminal connected tothe ground 7 in the usual manner, and has a conductor 8 extending from the other terminal thereof -to one contact 9 of a manual switch-10. The said switch is movable from the oil? position shown by full lines, to the non-automatic parking position 11, the automatic parking position'12, the automatic head light control position 13, the nonautomatic dimmer position 14, and the nonautomatic bright light position 15.

I When the switch 10 is in the position-13, it will be seen that current can pass through the conductor 16, throughthe arm l'l of an automatic switch, and through the conductor 18'leading to one terminal 19 of each bright light filament 20. The circuit to each of the bright light filaments is completed by the ground wires 21. Thus, with the switch 10 turned to the position 13, the bright light filaments will normally be in operation.

If, however, the car on which the device is utilized is approaching a well lighted area or is approached by another vehicle having its headlights on, the light from this external source will excite a light-sensitive photo-electric cell 22 which is mounted in a suitable position in the forward portion of the vehicle. This cell is of the type which is capable of generating an electromotive force when energized by light rays directed upon it.

The cell is connected by wires 23 with one coil 24 of an electromagnetic relay. The other coil 25 of the relay has one terminal electrically connectable by a switch 26 with the arm 17 of the automatic switch and has its other terminal connected by a wire 27 with a contact 28. The contact 28 is connected by wires 29 with the dim filaments 30 of the headlights. The dim filaments are also connected with the common ground 21.

When the light-sensitive cell is energized, a small current will be caused to flow through the coil 24. When the switch 10 is in the position 13 and the switch 26 in the full line position of Fig. 1, there is always a small amount of current passing through the relay coil 25, this current, however, being insufficient to cause illumination of the dim filaments 30. The coils 24 and 25 are so proportioned that neither,'when energized alone, is capable of attracting the automatic switch arm 1'? or relay armature, from the position shown by full lines in Fig. 1 in which it is normally maintained by a coil spring 31. When, however, both coils are energized, the coil 25 by current from the storage battery, and the coil 24 by the light-sensitive cell, suflicient pull is developed to attract the relay armature 17 from its spring-biased position to the position shown by dotted lines in Fig. 1, wherein it makes contact with the point 28. In this new position, the coil 25 is short circuited by the current pass ing directly through the arm 17 to the contact 28, but the coil 24, however, is capable of retaining the relay armature 1'? in the dotted line position against the eflort of the spring 31 as long as it is energized by the cell 22. When the cell 22 is no longer energized by light rays, the relay armature is retracted to its normal position shown by full lines by the spring 31. As before explained, the coil 25 may be made with a sufficiently high resistance to limit the current passing to the filament sections 30 to an economically low value affording no illumination when the relay armature 17 is not in contact with the point 28.

Fuses 32 and 33 may be interposed in the circuit to protect the system against abnormal conditions.

As an additional feature, the tail light, or the parking lights, or both, being indicated generally by the numeral 34, may be hooked up in the automatic circuit. When such is the case, a double armature is utilized, that is, a second armature 17' connected to the first armature 1'7 by a link 35. When the lever 10 of the manual switch is thrown to the position 12 for the automatic parking operation the switch 26 should be also thrown into engagement with contact '70 which is connected by a conductor 69 with the armature 1'7, and current will flow from the storage battery through the switch 10, through a conductor 35 to the armature 1'7. Said armature is adapted, when moved to the dotted line position, to complete the circuit to a conductor 36 leading to the tail and/or parking light 34. The operation is such that when the manual switch 10 is in the position 12 for automatic parking, that the tail and/ or parking light will not be on, the armature 17' being in the full line position. When, however, the photo-electric cell 22, suitably positioned, is affected by the lights of an approaching vehicle, there will be sufficient energization of the coils 24 and 25 to overcome the tension of the spring 31 andcause movement of the armature 17 to the dotted line position to cause operation of the light 34.

The switch 26 may be made to operate in conjunction with the switch 10, closing the circuit to armature 17 when the switch 10 is in position 13, closing the circuit to armature 1'7 when the switch 10 is in position 12, and being in an intermediate position when switch 10 is in all other positions.

If it is desired to have the parking light burning without the automatic control, the manual switch 10 is moved to the position 11 to compete the circuit through the conductor 3'7 to the light 34. Also, if it is desired to have the dimmers burning and unaffected by theautomatic control, the switch 10 may be moved to the position 14; In this position, the circuit is completed through a conductor 38 leading to the wire 29. Likewise, if it is desired to have the bright lights operate independently of the automatic feature, the switch 10 may be moved to the position 15 wherein the circuit to the bright lights is completed directly through the conductor 39.

It may thus be seen that with the system shown in Fig. 1, that the bright lights may be turned on subject to automatic transfer to the dimers as a result of the effect of light from an external source, that the parking and/or tail light may be made subject to being operated when the cell 22 is influenced by external light, and that either the dimmers, bright lights, parking and/or tail lights may be permanently illuminated in such a manner that they are unaffected by the automatic feature of the invention.

In view of the fact that the burning out of the filaments in the head lights is quite a common occurrence, it is desirable that provision be made to prevent automatic transfer from the bright filaments to the dim filaments when the dim filaments or the circuit in connection therewith are defective. The arrangement disclosed in Fig. 1 takes care of this contingency inasmuch as if the dim filament circuit is inoperable, there will be no current flowing through the coil 25. Inasmuch as the coil 24 even if energized by the cell 22 is not capable of alone moving the armature 17 to the position 28, there will be no transfer from the bright filaments to the dim filaments when the circuit to the dim filaments is inoperable. It is obvious that this feature may be so designed as to provide for a transfer if only one of the head light filament circuits is operable or to prevent transfer if only one of these circuits is operable.

In order to prevent the failure of the dim light circuit from affecting the operation of the automatic tail and/or parking light feature, an addi tional connection 40 to a ground switch 41 may be provided to insure a circuit through coil 25. This ground switch 41 is preferably made a part of the switch 10 and may be arranged to close the circuit only when the position of automatic parking or the position 12 is selected.

The arrangement disclosed in Fig. 1 may be utilized in the same identical manner in connec tion with head lights having two bulbs instead of the single double filament bulb. This modification is shown in Fig. 2 wherein the numeral 20' designates the bright light bulb, and the numeral 30' the dim light bulb. Inasmuch as the circuit connections are identical to that shown in Fig. 1, Fig. 2 only shows a fragment thereof.

In Fig. 3 an additional feature which may be incorporated, is illustrated. This feature provides for the transfer from the bright light to the dimmer when the circuit to the bright lights is defective and also for transfer from the dimmer to the bright light when the circuit to the dimmer is defective. The arrangement also provides for the automatic transfer from the bright light to the dimmer when the light-sensitive cell is energized by the lights of an approaching vehicle and when the circuit to the dimmers is not defec- 'tive.

Referring to this figure, the storage battery is indicated by the numeral 42, and said battery has one terminal connected to the ground, as at 43, and has another terminal connected by a wire 44 with a switch 45. The switch is adapted to make and break the circuit to a contact 46 which is connected by means of a wire 47 with a movable armature 48. One wire 49 extends from the armature 48 to a coil 50 of a multi-coil relay. The other end of the coil 50 is connected by a conductor 51 with a contact point 52. Another coil 53 of the relay is in connection with the contact point 52 and also by means of a conductor 54 with the dim filament 55 of the headlight bulb 56. Suitable ,connection with the ground is made through a conductor 57.

Another conductor 58 leading from the armature 48 connects with a relay coil 59, and the other end of the latter is connected by a conductor 60 w'th a contact point 61. Still another coil 62 forming part of the relay, has one end in connection with the contact point 61 and the other endin connection through a conductor 63 with the bright light filament 64 ofthe head light. Still anothercoil 65 is connected by means of conductors 66 with a light-sensitive electric cell 67. A coil spring 68 normally tends to hold the armature 48 with its free end in engagement with the contact 61.

The coils 50 and 53 are mounted on a common pole-piece and are in cumulative relationship tending to attract the relay armature to the position 52 shown by dotted lines in Fig. 3. The coils 59 and 62 are also mounted in cumulative relat'onship on their pole-piece and tend to attract the relay armature to the position 61 shown byfull lines. The coil 65 in connection with the light-sensitive cell is in differential relationship on the pole-piece carrying coils 59 and 62, and tends to demagnet'ze the pole-piece when all of the coils are energized. Coils 50, 59 and65 are of relatively high resistance, having a large number of turns of wire, while coils 53 and 62 are of relatively low resistance, having a small number of turns of wire.

. Coils 50 and 53 are so proportioned that their cumulative effect, when the relay armature is in the position 61 shown by full lines, is insufficient to attract the armature from this position to the dotted line position against the tension of the spring 68 and the pull of the coil 62, as long as the head light current through the filament section 64 is flowing through the coil 62, and as long as the coil 65 is not energized. It is to be noted that the coil 59 when the armature is in the position shown by full lines, is short circuited and therefore exerts no pull on the relay armature 48. I

Coils 50 and 53 are further so proportioned that their cumulative effect, when the coil 65, energized by current from the light-sensitive electric cell 67, de-magnetizes the pole-piece on which coils 59 and 62 are mounted, is suflicient to attract the armature against the remaining effect of coil 62 and the spring 68. It is to be observed that the coil 50 is short circuited by the armature 48 when the latter is in the dotted line position so that it no longer exerts a pull on said armature. The coil 53 is therefore so proportioned that it is capable of holding the relay armature and contact arm in the dotted line position against the pull of the spring 68 and the combined effect of current through the coils 59 and 62, as long as current flows through the coil 53 and the dim filament section circuit, and as long as 'the coil 65 continues to de-magnetize the opposing polepiece due to current from the cell 67.

When the exciting light rays are no longer 1 directed upon cell 67, then the current through the coil 65 ceases, and the pole-piece is no longer de-magnetized. When this situation occurs, the cumulative effect of the coils 59 and 62 together with the pull of the spring 68 are suflicient to atl tract the relay armature and contact arm back to the full line position.

Ifthe dim filament section circuit is inoperative due to defective wiring, burned out filament or the like, no current will flow through the coils 1 50 and 53, these being in series with the dim filament section, and no pull will be exerted upon the relay armature to tend to move it and the contact arm from the full line position to the dotted line position even when light rays are l directed upon the cell 67 to generate current in the coil 65. The spring 68 will therefore continue to maintain the relay armature and contact arm in the full line position.

Thus it is apparent that the. relay armature 1 "will not transfer to the dotted line position under the influence of light rays directed upon the cell 67 if in doing so it cannot effect a completed circuit to the dim filament 55. In addition, if when the relay armature is in the dotted line position, the dim filament circuit should become inoperable due to a burned out filament or defective wiring, the relay armature and contact arm will automatically return to position 61, thereby reestablishing connection to the bright filament 1 circuit. This is due to the fact that there will be no longer any current through the coil 53 tending to hold the armature in the dotted line position.

If in operating the lights, the relay armature 1 being in the full line position, establishing connection to the bright filament 64, the bright circuit fails due to burning out of the filament or to a defect in the wiring, the relay armature and contact will automatically transfer to the dotted line position under the influence of the coils 50 and 53, due to the failure of current through the coil 62. The spring 68 is so constructed as to permit this transfer when the coil 62 is no longer energized. The coil 65 is so proportioned that it cannot, even when energized, and aided by the spring 68, maintain the relay in the full line position against the pull of the coils 50 and 53.

It is thus apparent that failureof the bright filament circuit will automatically cause the transfer of the connections to the dim filament circuit, and that failure 01' the dim filament circuit will also automatically cause a transfer of the connections to the bright filament circuit. It is also apparent that the transfer from the bright to the dim circuit will be effected whenever the cell 67 is excited by light rays providing that the dim filament circuit is operable.

For simplicity of showing, only one head light has been illustrated in Fig. 3. It is obvious, however, that the arrangement may be wired in connection with any number of lights. It is also obvious that it is well adapted for use without variation in connection with headlamps each having two lights of the same or differing candlepower for substantially the same purpose. It is also obvious that a switching arrangement similar to that illustrated in Fig. 1 may be utilized in connection with the circuit of Fig. 3 to provide for a manual selection of circuits independently of the automatic control, and that the parking and tail light features illustrated in Fig. 1 may also be incorporated in the circuit of Fig. 3. It is also possible to provide still greater insurance against light failure by installing additional head light circuits and relays to cause successive transfer from one circuit to another, in place of limiting the number of circuits to two.

While the form of light-sensitive cell shown in the diagrams and described above is preferred for its simplicity and low cost, it is obvious to one skilled in the art, that other forms of light-sensitive cells, including any of the various forms of photo-electric cells or selenium cells, together with such auxiliary batteries and other apparatus as may be necessary to render the light-' sensitive cell efiective, can be substituted for the form of cell described in the disclosure. Also, the single relay structure shown may be separated into two or more components, or a combination of thermal and electromagnetic relays may be used.

And further, while reference is made in the disclosure and claims, to bright anddim light circuits, these being commonly used terms, it is obvious that these terms do not necessarily relate to the relative candlepower ratings of the lights employed, but rather to the practical result achieved. By suitable disposition of two lights or the two sections of a double-filament light with respect to the reflector and lens of a headlamp, the rays from one light element may be focused at a relatively long distance down the roadway, affording the bright light condition, while the rays from the other light element may be focused in a more downward direction at a relatively short distance down the roadway, affording what is frequently termed dim illumination. It is evident, therefore, that the light circuits described by the common terms dim and bright may containlights of the same or differing candlepower.

Other changes and modifications may be made without departing from the spirit of the invention, and all of such changes are contemplated as may come within the scope of the claims.

What I claim is:

l. A light controlling device for use in vehicles having a bright light circuit and a dim light circuit comprising a light-sensitive cell, a source of current, a contact arm in connection with said source of current and movable from circuit completing position with respect to one of said circuits to circuit completing position with respect to the other of said circuits, means normally urging said contact arm to bright light circuit completing position, an electromagnet positioned to urge said contact arm to dim light circuit completing position and having a coil through which current is permitted to flow from the source to the dim light circuit, the coil being so proportioned that the current normally flowing therethrough is insufficient for effective illumination of the dim lights and is ineffective to alone cause movement of the contact arm, and a second coil energized when light rays are directed upon the light-sensitive cell cooperable with said first coil to cause movement of the contact arm to complete the dim light circuit, the contact arm in said new position short circuiting the current around said first coil.

2. A light controlling device for use in vehicles having a bright light circuit and a dim light circuit comprising a light-sensitive cell, a source of current, a contact arm in connection with said source of current and movable from circuit completing position with respect to one of said circuits to circuit completing position with respect to the other of said circuits, means normally urging said contact arm to bright light circuit completing position, an electromagnet positioned to urge said contact arm to dim light circuit completing position and having a coil through which current is permitted to flow from the source to the dim light circuit, the coil being so proportioned that the current normally flowing therethrough is insufiicient for effective illumination of the dim lights and is inefiective to alone cause movement of the contact arm, and a second coil energized when light rays are directed upon the light-sensitive cell cooperable'with said first coil to cause movement of the contact arm to complete the dim light circuit, the contact arm in said new position short circuiting the current around said first coil, the coil which is operable by the light-sensitive cell being so proportioned that the current flowing therein is insufiicient to alone cause movement of the contact arm to prevent said movement when the dim light circuit is defective.

3. A light controlling device for use in vehicles having a bright light circuit, a dim light circuit, and an auxiliary light circuit comprising a lightsensitive electric cell capable of generating an electromotive force when excited by light rays directed thereon, a source of current, a contact arm movable from circuit completing position with respect to said bright light circuit to circuit completing position with respect to said dim light circuit, a second contact arm movable with said first contact arm from a position in which said auxiliary light circuit is broken to a position in which said auxiliary light circuit is completcd, means rendered operable by current generated by the light-sensitive cell for moving the first contact arm to a position to complete the dim light circuit and for moving the second contact arm to circuit making position with respect to the auxiliary light circuit, and a switch for selectively connecting the source of current with said bright and dim light circuits and with said auxiliary light circuit.

4. A light controlling device for vehicles having a plurality of circuits comprising a light-sensitive cell, a source of current for said circuits, means rendered operable by said light-sensitive cell when light rays are directed thereon for automatically causing breaking of one of said circuits and mak ing of the other of said circuits, and means operable in response to a defect in one of said circuits for preventing automatic transfer to said circuit.

5. A light controlling device for vehicles having a plurality of circuits comprising a. lightsensitive cell, a source of current for said circuits, means rendered operable by said light-sensitive cell when light rays are directed thereon for automatically causing breaking of one of said circuits and making of the other of said circuits, and means operable in response to a. defect in either of said circuits for causing automatic trans-' fer to an operable circuit if said defective circuit has been in use and for preventing transfer to said defective circuit if an operable circuit has been in use.

6. A light controlling device for vehicles having two circuits comprising a source of current, an electromagnet having a pair of coils interposed in cumulative relationship between thesource of current and each of said circuits, a contact arm connected with the source of current and movable from a position in which one of the coils of the electromagnet of one circuit is short circuited to a position in which one of the coils of the electromagnet of the other circuit is short circuited, said electromagnets acting upon the contact arm in opposing directions, and means aiding the electromagnet of one circuit in holding the contact arm in short circuiting position with respect to said circuit as long as said circuit is operable.

'l. A light controlling device for vehicles having a plurality of circuits comprising a source of current, an electromagnet having a pair of coils interposed in cumulative relationship between the source of current and each of said circuits, a contact arm connected with the source of current and movable from a position in which one of the coils of the electromagnet of one circuit is short circuited to a position in which one of the coils of the electromagnet of the other circuit is short circuited, said electromagnets acting upon the contact arm in opposing directions, means aiding the electromagnet of one circuit in holding the contact arm in short circuiting position with respect to said circuit as long as said circuit is operable, a light sensitive cell, and means energized when light rays are directed upon said cell and cooperable with the electromagnet of one of the circuits for causingmovement of the contact arm to short circuiting position with respect to the other of said circuits when said other circuit is operable.

8. A light controlling device for vehicles having bright and dim light circuits, comprising a source of current for said circuits, and means including a light-sensitive cell for establishing connections from the current source to the bright light circuit when light rays are not directed upon the light-sensitive cell, and for automatically transferring connections from the current source to the dim light circuit when light rays are directed upon the light-sensitive cell, said means including provision whereby transfer of connections to the dim light circuit in response to the light-sensitive cell is automatically prevented if a defect exists in the dim-light circuit rendering said dim light circuit inoperable to effect illumination.

9. A light controlling device for vehicles having bright and dim light circuits comprising a source of current for said circuits and means including a light-sensitive cell for establishing connections from the current source tothe bright light circuit when light rays are not directed upon the light-sensitive cell, and for automatically transferring connections from the current source to the dim light circuit when light rays are directed upon the light-sensitive cell, said means including provision whereby if a defect exists or occurs in one of the circuits which would render that circuit inoperable to efiect illumination, transfer of connection to the other circuit is automatically established, or if already established is automatically maintained, regardless of the functioning of the light-sensitive cell.

10. A light controlling device for vehicles having bright and dim light circuits comprising a source of current for said circuits and means including a light-sensitive cell, for establishing connections from the current source to the bright light circuit when light rays are not directed upon the light-sensitive cell and for automatically transferring connections from the current source to the dim light circuit when light rays are directed upon the light-sensitive cell, said means including provision whereby transfer of connections to the dim light circuit in response to the light-sensitive cell is automatically prevented if a defect exists in the dim light circuit which would render it inoperable to efiect illumination and further to cause automatically re-establishment of the bright light circuit if such defect occurs while connections to thedim light circuit are made in response to the light-sensitive cell.

11. A light controlling device for use in vehicles having two light circuits, comprising a source oi. current, a light-sensitive cell, a contact arm in connection with said source of current andmovable to transfer connection from the current source to one or the other oi the light circuits, means normally urging the contact arm to the first of said circuit connection, positions, and

eletromagnetic means positioned to urge the contact arm to the second of said light circuit connection positions, said electromagnetic means including two magnet coils; one coil being suitably arranged to connect in series with the said second light circuit to eifect a complete circuit from the current source through said coil and said light circuit when the contact arm establishes connection to the said first light circuit, and to be substantially de-energized when the contact arm establishes connection to said second light circuit, the said second coil being suitably arranged to be energized when light rays are directed upon the light-sensitive cell, the coils and their related magnetic circuit being so proportioned that neither when energized alone is capable of moving said contact arm from its first position but capable when both coils are energized of moving the contact arm to its second position and the second coil being further so proportioned that when energized it is capable of retaining the contact arm when in its second position.

12. A light controlling devicefor vehicles having two light circuits comprising a source of current, a light-sensitive cell, a contact arm in con nection with said source of currentand movable to transfer connection from the current source to one or the other of said light circuits, means normally urging said contact arm to the first of said light circuit connection positions and electromagnetic means positioned to urge said contact arm to the second of said light circuit connection positions, said electromagnetic means including three magnet coils, two of said coils being suitably arranged to connect in series with said second position, one of said two coils being arranged to be substantially de-energized when the contact arm establishes connection to said second light circuit, the second of said two coils remaining in circuit in series with said second light circuit, and the third of said coils being suitably arranged to be energized when light rays are directed upon the light-sensitive cell, the coils and their related magnetic circuit being so proportioned that neither the said two coils when energized together, nor the third coil when energized alone are capable of moving the contact arm from its normal position but capable, when all three coils are energized, of moving the contact arm to said second position and said second and third coils being further so proportioned that neither alone is capable of retaining the contact arm in its second position, but both said second and third coils when cooperating being capable of retaining the contact arm in its second position.

13. A light controlling device for vehicles having two light circuits comprising a source of current, a light-sensitive cell, a contact arm in connection with said current source and movable to transfer connection from the current source to one or the other of said light circuits, means normally urging the contact arm to the first of said light circuit connection positions and electromagnetic means positioned to urge the contact arm to the second light circuit connection position, said electro-magnetic means including three magnet coils, one of said coils being positioned to be connected in series between the current source and the second light circuit when the contact arm is in its normal position, and to be substantially de-energized when the contact arm is in its second connection position, the second coil being suitably arranged to connect in series with the second light circuit when the contact arm is in its second position and the third coil being suitably arranged to be energized when light rays are directed upon the light-sensitive cell, the coils and their related magnetic circuits being so proportioned that both the first and third coils must be energized to move the contact arm from its normal to its second position, and both the second and third coils must be' energized to retain the contact arm when in its second position.

14. A light controlling device for vehicles having two light circuits comprising a current source for said circuits, acontact arm in connection with said current source and movable to transfer connections from the current source to one or the other of said light circuits, means normally urging the contact arm to the first of said light circuit connection positions and an electro-magnetic structure including three magnet coils, one coil being positioned to be connected in series with the first light circuit when the contact arm is in its normal connection position, a second coil being positioned to be connected in series with the second light circuit when the contact arm is in its second connection position, and a third coil positioned to be connected in series with the second light circuit and the current source when the contact arm is in its normal connection position, said electro-magnetic structure and related coils being so arranged that the first coil aids the contact arm to retain its normal position, the second coil tends to retain the contact arm in its second position, and the third coil urges the contact arm from its normal to its second position; the coils and their related magnetic circuits being so proportioned that when the contact arm is in its normal position, the first coil is capable of retaining it in said normal position against the efforts of the other two coils so long as current of a desired magnitude fiows through the first light circuit, and so that the second coil is capable of retaining the contact arm in its second position against said first means urging the contact arm to its normal position so long as current of a desired magnitude flows through the second light circuit, and the third coil is capable, when a current of a desired magnitude flows through it of moving the contact arm from its normal position when current through the first coil is reduced in magnitude due to a defect in the first light circuit rendering it inoperable to effect illumination, the resistance of the third coil being of such value as to prevent effective illumination by the second light circuit when the contact arm is in its normal position.

15. A light controlling device for vehicles having two light circuits comprising a current source, a light-sensitive cell, a contact arm in connection with said current source and movable to transfer connections from the current source to one or the other of said light circuits, means normally urging the contact arm to the first of said light circuit connection positions and an electro-magnetic structure including five magnet coils, the electro-magnetic structure having two portions each including two coils, one portion being positioned to urge or retain the contact arm to said first position, the second portion being positioned to urge or retain the contact arm to said second position, the first portion having one coil positioned to be connected in series between the current source and said first light circuit when the contact arm is in its normal position and the second coil being positioned to be connected in series between the current source and first light circuit when the contact arm is in its second position and to be substantially de-energized when the contact arm is in its normal position, and the second portion having one coil positioned to be connected in series between the current source and said second light circuit when the contact arm is in -its second position and the second coil being positioned to be connected in series between the current source and the second light circuit when the contact arm is in its normal position, and to be substantially de-energizcd when the contact arm is in its second position, the coils and related magnetic circuits being so proportioned that the first coil of the first portion aided substantially only by said first means is capable of retaining the contact arm in its normal position against the combined and unaided efforts of the two magnet coils of the second portion so long as current of a desired magnitude flows through said first coil and first light circuit, and the second coil of the first portion optionally in conjunction with the first coil and aided by said urging means is capable of moving the contact arm from its second to its normal position against the combined and unaided efforts of the two magnet coils of the second portion when current of a desired magnitude flows through said second coil, and the first coil of the second portion being capable of retaining the contact arm in its second position against the unaided eflort of said first means so long as current of a desired magnitude flows through said first coil, and the second coil of said second portion optionally in conjunction with the first coil of said portion being capable of moving the contact arm from its normal to its second position against the unaided effort of said first means so long as current of a desired magnitude flows through said second coil, and the fifth coil of the electro-magnetic structure being connected so as to be energized when light rays are directed upon the light-sensitive cell and being positioned when energized to urge the contact arm from its normal to its second position, but capable of effecting this movement only when aided by the eiforts of said first two coils of the second portion.

16. A light controlling device for use in vehicles having a first light circuit and a second light circuit comprising a light sensitive cell, a source of current, a contact arm in connection with said source or current and movable from circuit completing position with respect to one of said circuits to circuit completing position with respect to the other of said circuits, means normally urging said contact arm to first light circuit completing position, an electromagnet positioned to urge said contact arm to second light circuit completing position and having a coil through which current is permitted to flow from the source to the second light circuit, the coil being so proportioned that the current normally flowing therethrough is insufficient for effective operation of the second light circuit and is inefiective to alone cause movement of the contact arm, and a second coil energized when light rays are directed upon the Eight-sensitive cell cooperable with said first coil to cause movement of the contact arm to complete the second light circuit, the contact arm in said new position short circuiting the current around said first coil.

17. A light controlling device for use in vehicles having a first light circuit, a second light circuit, and an auxiliary light circuit comprising a lightsensitive electric cell capable of generating an electromotive force when excited by light rays directed thereon, a source of current, a contact arm movable from circuit completing position with respect to said first light circuit to circuit completing position with respect to said second light circuit, a second contact arm movable with said first contact arm from a position in which said auxiliary light circuit is broken to a position in which said auxiliary light circuit is completed, means rendered operable by current generated by the light-sensitive-cell for moving the first contact arm to a position to complete the second light circuit and for moving the second contact arm a to circuit making position with respect to the auxiliary light circuit, and a switch for selectively connecting the source of current with said first 

